Electrical attachment-plug.



P. s, MCLEAN. ELECTRICAL ATTACHMENT FLUG.- APF'LICATION FILED APR. 4| 1916.`

' "Anm A s l Patented May 29, 1917. k7 2 snaps-SHEET l.

P. S. MCLEAN. ELECTHlCAL ATTACHMENT PLUG. APPLICATION Flu-:n APH. 4.4916.

' 1,228,331 mme@ 'my 29, 1917..

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' l PHILIP S. IVICLEAN, OF BLOOMFIELD, NEW JERSEY.

l:ElLlilC'IRICJeL ATTACHMENT-PLUG.

To all wwm t may concern Be it known that I, Pnimr S. MCLEAN, a. citizen of the United States of America, residing at Bloomfield, New Jersey, have invented a new and useful Electrical Attachment-Plug, of which; the following is a specification.

My invention relates particularly to attachment plugs of ithe swivel type, and the general objects ofthe invention are to improve, simplify and reduce the cost of devices of this character.

A special object of the invention is to provide a swivel plug whose parts can be readily separated for wiring purposes and in which the parts, when the plug is assembled, will be held positively locked together.

A further object is to provide a plug of good mechanical strength, having high curvrent carrying capacity and in which the current carrying parts are well insulated and properly protected.

In the accomplishment of the foregoing and other objects, I employ an insulating base on which the circuit terminals are mounted and secure the rotating screw shell contact on this base by means of an end contact member mounted on 'the base, suitable insulation being interposed to prevent a short connection between the end contact and rotatable screw shell.

Another feature of the invention is the making of the end contact readily releas able from its holding position so as to permit easy separation of the two relatively rotatable members of the plug.

Other features of the invention have to do with the details of construction, etc., all ot which willappear as the specification proceeds, attention being directed to the'accompanying .drawings forming `part hereof and wherein I havef illustrated practical forms the invention may take.

In said drawings:

l Figure 1 is a vertical sectional view of a plugl embodying the invention. n

Fig. 2 is another sectional view taken substantially on the plane of the line 2 2, Fig. 1.

Fig. 3 is a view similar to Fig. 1 showing the end contact in released position to permit separation of the parts.

Fig. l is a drop perspective view of the insulating base member and the several parts ca riad thereby. 4

Specification offLetters Patent. Patented Riny 29?, T917.

Application ined april 4, 191e.

Serial No. 88,790.

Fig. 5 is a view showing the terminal carrying insulating base member separated from the screw shelh Fig. 6 is a sectional View similar to Fig. 1 illustrating a slightly different form of the invention wherein the scre\vsliell-retain ing endcontact member is held seated in its securing position by a spring instead of a screw such as shown in the lirst form.

Fig. 7 is another sectional view showing the end contact in this form of construction released to permit separation of the parts.

Fig. S is a top plan View of the terminal carrying base.

F ig. 9 is a detached perspective view of the end contact member in this form of construction.

F ig. 10 is a view illustrating the blank from which this end contact may be made.

with the center or end contact 2O and the other being provided with a laterally outstanding foot 21 seated in a recess 22 in the iiange ot the base and providing a contact for engagement by the liange 23 turned in at the lower end of the screw shell contact 2l.

The circuit terminal 18 is secured in place in the construction illustrated, by forming it with outstanding lugs 25 engaging in an undercut groove-way 2G formed in the side of the base. These outstanding lugs 25 may be produced by simply punching a hole in the body of the circuit terminal as indicated at 27 so as to spread the metal at this point and produce projecting lugs at the opposite edges of the terminal. lt will be seen from this that this circuit terminal may besecured in place by simply dropping it into `the upper end of the undercut groove-way. The binding screw 28m? this terminal may engage in a transversely extending seat A)termed at the bach of the undercut grooveand at the rear by supporting and bracing way to prevent accidental disengagement of the circuit terminali.

The other circuit terminal 17 may seat in a socket 30 provided for it in the top'of the insulating base and an insulating wall 31 is preferably provided to form an insulating barrier between the two circuit` terminals.

The end contact member 2() is of novel construction embodying in addition to the contact making end portion thereof, a'shank extension 32 terminating in a laterally projecting lug 33 which makes holding engagement with the flange portion of the screw shell contact, suitable insulating medium being interposed at some point in this line of connection. This insulating medium consists in the present disclosure of a washer `or bushing 34 of insulating material lining the lower end portion of the screw shell contact and bearing on the inturned flange 23.

As most clearly shown in Figs. 1 and 3, the shank extension 32' of the end contact is received in a longitudinally extending passage 35 extending upward from the lower end of the base, said passageopening laterally out through the side of the base at a point above the outstanding flange 16, as indicated at 36, to permit the holding lug 33 to project laterally out over the insulating washer lin the lower end of the screw shell. In the holding position of the end contact, the holding lug 33 is preferably backed up both at the top walls 37 and 38 so as to prevent the end contact being sprung and the parts separated b y force. Further, in the normal position of the parts, the exposed end portion of the end contact seats in a socket 39 in the end of the .base shaped to receive it.

screw shell contact.

upper circuit terminal.

In the normal condition of the plug, as indicated in Fig. 1, the center. securing screw 19 holds the end contact seated in holding.

position with the holding lug thereof overlying -the insulatin shoulder in the lower end of the shell con act. The shell contact is thus rotatably confined to the base. When it is desired to release the plug, it is merely necessary, in this form of the invention, to p loosen the holding screw 19 as indicated in Fig. 3, far enough to permit the end Contact to drop downward and inward far enough for the holding lug thereon to clear the insulating shoulder in the lower end of the In this condition the screw shell can be readily slipped off the base for the purpose of like. The upper end of the holding screw may be headed over as indicated at 40 to prevent the screw being wholly withdrawn and disengaged. from the The insulating shoulder preferably eX- tends inward past the inner periphery of the inturned lange `on the shell, as indicated in Figsfl, 2 and 3, so as to prevent the pos- 4wiring or unwiring tl t u te d.

- ia a pu n ing lug engaging the flange during separation thermore, the insulating bushing preferably extends up into the screw shell some distance above the holding' lug, and the end of the holding lug preferably terminates just short of the inner wall ofthe insulating lining, as indicated at 41'in Fig. 1, so as 4to avoid any. possibility of the end of the holding lug working through the insulating lining.

The parts of opposite polarity may if, desired be further insulated by the provision of an insulating cap 42 resting on top of the insulating base and covering the upper circuit terminal.

The screw shell is provided at its upper outer end with a suitable hand-hold 43 preferably of insulating material, a convenient method of securing the screw shell and handhold together being to mold the hand-hold about out-turned flanges or fingers 44 provided at the upper end of the screw shell.

In the second form of the invention illustrated, the end contact 45 is provided with a shank extension 46 and with a holding lug 47 as before, and in addition thereto, is provided with an upstanding stud 48 provided at its upper end with a circuit terminal member 49 with which a binding screw 50 or the like may be engaged. Fig. 10 illustrates how this end contact may be blanked out from a flat strip of metal 5l, the stud 48 being formed as an integral member cut therefrom along the dotted lines 52. Y

The end contact is in this form shown normally seated in its holding position by means of a Yspring 53 seated in a pocket 54 in the top of the insulating base and engaged beneath the circuit terminal head on the updicated in Fig. 7 a thumb nail recess 55 being usually provided to permit the engagement of the thumb nail beneath the end contact for the -purpose of thus releasing the arts. This ready separability ofthe two parts of the plug is of considerable advantage in that the parts can be instantly separated without any prior manipulation of screws or other elements. At the same time it will be noted that in the construction shown, the parts when assembled, are positively locked together and4 accidental separation of the same is prevented, it being noted to separate the parts is taken up by the r1gid supporting wall 3,7a and 38a.

In'this form also, I have illustrated how the end contact may, as indicated in Fig. 6, be extended over so as to substantially close up the end of the passage 35 through which the shank46 of the end contact extends.

The insulating base of the plug is of such Furheir

simple construction that it can he readily molded from porcelain or any other suitalole insulating material, and as this material is cheaper than Imetal, l have illustrated in Figs. 6 and 7 how the base may he made comparatively long and the screw shell contact be ma de relatively short, it being merely necessary to make this screw shell contact long niough to take into the screw shell of the soclret which the plug is intended to fit.

Vlhat l claim is:

l. An attachment plug comprising an in sulating base, circuit terminals on said hase, a screw shell rotatable about the hase and provided with an inwardly projecting flange, a contact on the base connected with one circuit terminal and engaging with the screw shell contact, an end contact on the base connected with the other circuit terminal provided with a holding' lug to over-stand the inwardly projectingflange on the screw shell and means for shiitingthe end contfft lat-V erally to carry said holdinglug into position overstanding` said inwardly projecting flange.

2. ein attachment plugl comprising an in sulating hase, circuit terminals on. said hase, a screw shell contact rotatable about the baseand provided with an inwardly project ing flange, a Contact on the hase connected with one circuit terminal and engaging with the screw shell contact, an end Contact on the ba se electrically connected with the other circuit terminal and provided with holding lug overstanding the inwardly projectingflange on the screw shell contact to rotatably confine the saine to the hase and an insulating medium interposed between the end contact and shell contact.

3. in attachment plug comprising an insulating base, circuit terminals on said hase, a screw shell contact rotatable about the hase and provided with an inwardly projecting flange, a contact on the hase connected with one circuit terminal and engaging with the screw shell contact, an end contact movably mounted on the base electrically connected with the other circuit terminal and provided with a holding lug,- arranged in one position or' said end contact to overstand the inwardly projecting flange to hold the screw shell rotatably confined to the hase and inv anotherposition oi said end Contact to he clear oi the flange to release the screw shell from the hase and nieans'ior normally maintaining the end contact with the lugthereo in its` holding position.

rliifattachnrcnt plug comprising: an insulating lease. circuit terminals on said. hase, a screw shell contact rotatahle about the hase and provided with an inwardly projecting flange, a contact on the oase connected with one circuit terminal and en, ja,g'incf with the screw shell contact, an end contact relcae'ahly seated on the end of the hase electrically connected with the other Acircuit terminal and provided with a laterally e2;-

'tending lug' overlying the flange of the screw An attachment plug comprising an in? sulating hase, circuit terminals on said hase,

va screw shell contact rotatable about the base and provided with an inwardly projecting flange, a contaclt on the hase connected. with one circuit terminal and engaging with the screw shell contact, an end contact movahly mounted on the hase and provided with an outstanding lug arranged in one position oi" said end contactto hold the screw shell rotatably confined to the hase and in another position of the end Contact to release the screw shell from the hase and means for holding the end contact in its holding; position and for releasing it trom such holding position, said means providing a means of electrical connection between the end contact and the other circuit terminal,

6, An attachment plug comprisin an in sulating` hase'suhstantially circular in "torni and provided with an outstanding flange 'at the lower end thereof, said hase haring ii recess in one side thereofA with undercut walls, circuit terminal seated in said recess, having port-ions engaged behind said undercut walls and provided at its lower end with an outstanding foot portion hear ing on the flange el* the hase, a screw shell surrounding said hase and 4proiided with an end flange hearingu on said angularly outstanding; toot portion of the circuit tern'iinal, and readily releasahle means for detachahly confining the screw shell in posi' tion upon the hase.

'l'. An attachment plug comprising an insulating hase, circuit terminals on said hase, a screw shell contact rotatable about the loa-se and provided with an inwardly projecting langda contact on the hase connected with one circuit terminal and engaging with the screw shell contact, a holding member mounted on the hase and laterally shittahle thereon, and means extending longitudinally of the hase for shifting said holding; member laterally on the hase into position overstanding the inwardly projecting 'tlf-inge on the screw shell contact.

8. A n attachment plug comprising en in` sulatinri base, circuit terminals on said hase, a screw shell contact rotatable about the 'base and provided with an inwardly prrr ally shiftable thereon, a shoulder for holding said member laterally shifted in position overstanding the iange on the screw shell Contact, and a screw extending longitudinally of the base into engagement with the other circuit terminal adapted when tightened to hold the holding member in engagement with the shoulder on the base and in position overstanding the inwardly projecting fiange and when loosened to allow the holding member to move into position free of the inwardly projecting flange.-

9. An attachment plug comprising an insulating base, circuit terminals on said base, a screw shell contact rotatable. about the base and provided with an linwardly projecting flange, a Contact on the base connected with one circuit terminal and engaging with the screw shell contact, an end Contact on the base electrically connected with the other circuit terminal and provided vwith a holding lug overstanding the inwardly projecting flange on the screw shell contact to rotatably confine the same to the base and an insulating lining in the screw shell having an inwardly projecting 'shoulder above the flange thereof adapted to be engaged by the holding lug and said holding lug terminating short of the side wall of said in-l sulating of said side wall of the lining.

10. An attachment plug comprising an insulating base, circuit terminals on the upper portion of said base, a screw shell .contact rotatable about the base and inclosing said circuit terminals, said screw shell contact having an inwardly projecting flange7 an insulating cap applied to said insulating base and covering the circuit terminals thereon to thereby form an insulating barrier between lthe same and the surrounding screw shell contact,4 a contact on the base connected with one circuit terminal and engaging with the screw shell Contact, an end contact laterally shiftable on the base and having a lug adapted to overstandthe inwardly projecting flange on the screw shell Contact, a connection between said end contact and the other circuit terminal and an insulating lining in the screw' shell Contact having a shoulder above the inwardly projecting flange to be engaged by the holding lug.

PHILIP S. MOLEAN.

lining to thereby prevent wearing Copies of this patent may be 4obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

